The Bears believe Cutler was injured on a helmet-to-helmet hit from Houston's Tim Dobbins late in the second quarter of Sunday's loss. Cutler finished the half but sat out the final two quarters after showing concussion symptoms in Chicago's locker room at the break.

Cutler needs to be cleared by team physicians and independent neurological consultants before he can return. The same goes for Bears teammate Shea McClellin and 49ers quarterback Alex Smith, who also suffered concussions last week.

Lovie Smith gave mostly vague answers about Cutler. When asked if he expects his quarterback to practice Friday, the coach said, "Wait 'til tomorrow and see."

Smith also left open the possibility of Cutler playing without practicing this week, assuming he's cleared. But Smith wouldn't say if the Bears would hold out their quarterback even if the doctors gave the OK to play.

"I can't wait for us to get to the point where Jay is ready to play, and we'll make all those decisions then," Smith said. "First just (get him) ready to practice, and then we'll go to that next step."

The Bears crumbled after Cutler broke his right thumb in the 10th game last season, finishing at 8-8 after a 7-3 start, but they believe they have a solid backup this time in Campbell. He could be tested this week by one of the NFL's top defenses.